In recent years, dentistry treatments to form a denture by embedding an implant (artificial tooth root) in a tooth deficient portion have been performed. In such treatments, insertion holes for implant are drilled at tooth deficient portions by use of a drill attached to a drilling apparatus such as a handpiece, and at this time, a surgical guide is usually employed to drill a hole in order to guide the drill so that the hole for implant would be formed at a predetermined position and in a predetermined direction.
Into this surgical guide, a metallic guide ring (guide tube) is fitted to guide the drill to the surgical guide supported by jawbone, etc.
When the guide ring is employed to guide the drill for drilling a hole, it is required that adequate bone quantity is confirmed at the portion where the hole for implant is formed and no nerves or blood vessels are present at this portion.
In order to satisfy such requirements, in general, a CT scanning is conducted by use of an X-ray CT apparatus (Computed Tomography) in such a state that a surgical guide (a stent for diagnosis) is attached to the teeth of the patient, and the examination results by the CT scanned image are used to determine the insertion direction of the implant.
Various methods have been proposed as a method for determining the insertion direction of the implant.
For example, European Patent No. 1043960 describes a method for processing a hole for implant by a numerically controlled boring machine which moves in relation with an X-ray CT apparatus.
In this method, since the numerically controlled boring machine is additionally employed, the entire machine becomes large, the operation requires skillfulness and costs become high.
Further, as described in JP-A-2006-141561, a method has been proposed in that the CT scanned image of a jaw bone area of a tooth deficient portion is printed, the tooth deficient portion is cut out from the print, the cutout part is adhered to a teeth impression model, and then the adhered cutout part is given a mark showing the insertion position and direction of implant, and a hole for implant is drilled along this mark.
However, in this method, many operations are required as described above and the hole for implant is processed while visually observing the mark, whereby there is a concern that the hole for implant may not be processed correctly.